From: Haoran Luo <www@aegistudio.net>
To: zhangyoufu@gmail.com
Cc: axboe@kernel.dk, cgroups@vger.kernel.org,
linux-block@vger.kernel.org, tj@kernel.org
Subject: Re: [BUG] blk-throttle panic on 32bit machine after startup
Date: Mon, 18 Oct 2021 08:00:27 +0000 [thread overview]
Message-ID: <YW0pm5xcxgWnW98f@aegistudio> (raw)
(Sorry for the garbled message due to my mistaken the configuration of mutt)
I'm the college of the reporter and I would like to provide more
information.
The code in 5.15-rc6 in "blk-throttle.c" around line 791 is written as
below:
/*
* Previous slice has expired. We must have trimmed it after
* last
* bio dispatch. That means since start of last slice, we never
* used
* that bandwidth. Do try to make use of that bandwidth while
* giving
* credit.
*/
if (time_after_eq(start, tg->slice_start[rw]))
tg->slice_start[rw] = start;
I think this piece of code presumes all jiffies values are greater than
0, which is the initial value assigned when kzalloc-ing throtl_grp. It
fails on 32-bit linux for the first 5 minutes after booting, since the
jiffies value then will be less than 0.
next reply other threads:[~2021-10-18 8:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-18 8:00 Haoran Luo [this message]
-- strict thread matches above, loose matches on Subject: below --
2021-10-18 9:25 [BUG] blk-throttle panic on 32bit machine after startup Haoran Luo
2021-10-18 7:08 Youfu Zhang
2021-10-18 15:22 ` Liqueur Librazy
2021-10-19 17:45 ` Tejun Heo
2021-10-21 4:26 ` Youfu Zhang
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